xti_sctp.3

7号信令功能代码,为开源代码

draft-ietf-tsvwg-prsctp-00.txt
.]
associated with message that are sent on this transport endpoint.
The option value is formatted as a
.B t_scalar_t
that contains the lifetime (in milliseconds).
.\"
.\"
.TP 12
.B T_SCTP_ADD
This option determines whether the transport endpoint will support the add IP
extension
.RB ( ADD-IP " and " DEL-IP )
described in draft-ietf-tsvwg-addip-sctp-07.txt.
.[
draft-ietf-tsvwg-addip-sctp-07.txt
.]
The option value is formatted as a
.B t_scalar_t
that can have values
.BR T_YES " or " T_NO .
.sp
When set to
.BR T_YES ,
this option request that SCTP respond to ASCONF chunks with ADD-IP or DEL-IP
requests.  When set to
.BR T_NO ,
SCTP will refuse these requests for the transport connection.
This option can be set or read at any time during the transport connection
lifetime.
.\"
.\"
.TP 12
.B T_SCTP_ADD_IP
This option adds a IP address to an existing transport endpoint.
The option value is formatted as a
.B sockaddr_in
structure that contains the local IP address to add.
Option
.I T_SCTP_ADD
must be set to
.B T_YES
for this option to be valid.
.sp
If the transport stream is in a connected or connecting state, this invokes
the ASCONF procedure to add the IP address to the existing transport
connection.  If the transport stream is in a disconnected state, setting this
option will add the local IP address to the addresses bound with
.BR t_bind (3),
and acts as a hierarchal subsequent binding operation.
.sp
Note that if a transport endpoint was initially bound to
.IR INADDR_ANY ,
IP addresses may be automatically added to the transport connection
if new network interfaces are added to the system, or if existing network
interfaces are configured using
.BR ifconfig (8)
or equivalent commands.
.\"
.\"
.TP 12
.B T_SCTP_DEL_IP
This option deletes an IP address from an existing transport endpoint.
The option value is formatted as a
.B sockaddr_in
structure that contains the local IP address to delete.
Option
.I T_SCTP_ADD
must be set to
.B T_YES
for this option to be valid.
.sp
If the transport stream is in a connected or connecting state, this invokes
the ASCONF procedure to remove the IP address from the transport connection.
If the transport stream is in a disconnected state, setting this option will
remove the local IP address from the addresses bound with
.BR t_bind (3),
and acts as a hierarchal subsequent unbinding operation.
.sp
Note that if the transport endpoint was initially bound to
.IR INADDR_ANY ,
IP addresses may be automatically removed from the transport connection if
existing network interfaces are removed from the system, or if network
interfaces are reconfigured with
.BR ifconfig (8)
or equivalent commands.
.\"
.\"
.TP 12
.B T_SCTP_SET
This option determines whether the transport endpoint will support the add IP
extensions
.RB ( SET-PRIMARY )
described in draft-ietf-tsvwg-addip-sctp-07.txt.
.[
draft-ietf-tsvwg-addip-sctp-07.txt
.]
The option value is formatted as a
.B t_scalar_t
that can have values
.BR T_YES " or " T_NO .
.sp
When set to
.BR T_YES ,
this option request that SCTP respond to ASCONF chunks with SET-PRIMARY
requests.  When set to
.BR T_NO ,
SCTP will refuse these requests for the transport connection.
This option can be set or read at any time during the transport connection
lifetime.
.\"
.\"
.TP 12
.B T_SCTP_STATUS
This option conveys the association status  and the status associated with
each of the destination transport addresses forming the transport connection.
This is a read-only option.
The returned value is formatted as a
.B t_sctp_status
structure containing one
.B t_sctp_dest_status
structure for each destination transport address, formatted as follows:
.sp
.nf
\fC\s-1\
typedef struct t_sctp_status {
    t_uscalar_t curr_rwnd;   /* receive window */
    t_uscalar_t curr_rbuf;   /* receive buffer */
    t_uscalar_t curr_nrep;   /* dests reported */
    t_sctp_dest_status_t curr_dest[0]; /* primary dest */
} t_sctp_status_t;
.sp
typedef struct t_sctp_dest_status {
    t_uscalar_t dest_addr;   /* address */
    t_uscalar_t dest_cwnd;   /* congestion window */
    t_uscalar_t dest_unack;  /* unacknowledged chunks */
    t_uscalar_t dest_srtt;   /* smooth round trip time */
    t_uscalar_t dest_rvar;   /* rtt variance */
    t_uscalar_t dest_rto;    /* current rto */
    t_uscalar_t dest_sst;    /* slow start threshold */
} t_sctp_dest_status_t;
\s+1\fR
.fi
.RS
.PP
The
.B t_sctp_status
structure has the following fields:
.TP 12
.I curr_rwnd
is the current advertised receive window in bytes.
.TP 12
.I curr_rbuf
is the current receive buffer size in bytes.
.TP 12
.I curr_nrep
is the number of
.B t_sctp_dest_status
structure that follow this structure.
.PP
The
.B t_sctp_dest_status
structure has the following fields:
.TP 12 12
.I dest_addr
is the address associated with this specific
.B t_sctp_dest_status
structure.
.TP 12
.I dest_cwnd
is the congestion window for the given destination transport address in bytes.
.TP 12
.I dest_unack
is the number of unacknowledged DATA chunks outstanding to the given
destination transport address in chunks.
.TP 12
.I dest_srtt
is the smoothed round trip time for the destination transport address in
milliseconds.
.TP 12
.I dest_rvar
is the round trip time variance for the destination transport address in
milliseconds.
.TP 12
.I dest_rto
is the current value of the round trip timeout for the destination transport
address in milliseconds.
.TP 12
.I dest_sst
is the current value of the slow start threshold for the destination transport
address in bytes.
.RE
.\"
.\"
.TP 12
.B T_SCTP_TSN
This option determines the SCTP Transmit Sequence Number that is to be associated
with a given data transmission.  The option value is formatted as a
.B t_scalar_t
that contains the numeric value of the SCTP Transmit Sequence Number.
This options is used with
.BR t_optmgmt (3).
The SCTP transport provider determines which values will be used on all packets sent with
.BR t_snd "(3), " t_sndv "(3), " write "(2) or " writev (2).
The current value, when read, using
.BR t_optmgmt (3),
will return the value that was contained in the last packet read with
.BR t_rcv "(3), " t_rcvv "(3), " read "(2) or " readv (2).
.\"
.\"
.TP 12
.B T_SCTP_DEBUG
This option determines implementation specific debugging features.
The option value is formatted as a
.BR t_scalar_t ,
that can be one of the following values:
.RS
.TP 12
.I T_SCTP_OPTION_DROPPING
the stream will drop packets at the software level for debugging purposes.
.TP 12
.I T_SCTP_OPTION_BREAK
the stream will break the first destination address at intervals for debugging
purposes.
.TP 12
.I T_SCTP_OPTION_DBREAK
the stream will break destination addresses in both directions at intervals
for debugging purposes.
.TP 12
.I T_SCTP_OPTION_RANDOM
the stream will drop packets at random at the software level for debugging
purposes.
.RE
.\"
.\"
.SH FUNCTIONS
.PP
.\"
.\"
.SS t_accept\fR(3)
.PP
.PP
SCTP supports this XTI library call as described in
.BR t_accept (3),
with the additional considerations described here.
.PP
When the XTI user provides a transport endpoint address in
.IR call->addr ,
the address can be an array of
.B sockaddr_in
structures, each indicating a local address for the responding endpoint.
If this list of addresses does not include the destination address of the
connection indication, the set of addresses will be expanded by the SCTP
provider to include the destination address of the connection indication.
.PP
SCTP provides a number of options, described in
.IR \(lqOPTIONS\(rq ,
above, that may be included in this XTI call
in the
.I call->opt
parameter to change local and end-to-end characteristics of the transport
endpoint accepting the connection.
The options of end-to-end significance that can be included in this XTI
library call are:
.TP 12
.I T_SCTP_ISTREAMS
sets the number of incoming streams for the transport connection.  This value
is only significant if it is lower than the value requested by the peer in the
options returned from the call to
.BR t_listen (3).
.TP 12
.I T_SCTP_OSTREAMS
sets the number of outgoing streams for the transport connection.  This value
is only significant if it is lower than the value required by the peer in the
options returned from the call to
.BR t_listen (3).
.TP 12
.I T_SCTP_ECN
sets whether explicit congestion notification is supported on the transport
connection.  This value is only significant if the peer indicates that it
supports explicit congestion notification in the options returned from the
call to
.BR t_listen (3).
.TP 12
.I T_SCTP_ALI
sets the adaptation layer information specifying the local endpoint
capabilities that are available on the transport connection.
.PP
The options of local significance that can be included in this XTI call
include (other options of local significance may also be included):
.TP 12
.I T_SCTP_HEARTBEAT_ITVL
sets the heartbeat interval to be used on all destination addresses during the
connection.
This value can be changed for specific connection by providing this option to the
.BR t_accept (3).
This value may be changed during the transport connection using the
.I T_SCTP_HB
option to
.BR t_optmgmt (3).
.TP 12
.I T_SCTP_RTO_INITIAL
sets the initial retransmission timeout for all destinations.
This value can be changed for specific connection by providing this option to the
.BR t_accept (3).
This value may be changed during the transport connection using the
.I T_SCTP_RTO
option to
.BR t_optmgmt (3).
.TP 12
.I T_SCTP_RTO_MIN
sets the minimum retransmission timeout interval for all destinations.
This value can be changed for specific connection by providing this option to the
.BR t_accept (3).
This value may be changed during the transport connection using the
.I T_SCTP_RTO
option to
.BR t_optmgmt (3).
.TP 12
.I T_SCTP_RTO_MAX
sets the maximum retransmission timeout interval for all destinations.
This value can be changed for specific connection by providing this option to the
.BR t_accept (3).
This value may be changed during the transport connection using the
.I T_SCTP_RTO
option to
.BR t_optmgmt (3).
.TP 12
.I T_SCTP_PATH_MAX_RETRANS
sets the maximum number of times that a retransmission will be directed at a
destination address until the destination address is deemed inactive.
This value can be changed for specific connection by providing this option to the
.BR t_accept (3).
This value may be changed during the transport connection using the
.I T_SCTP_RTO
option to
.BR t_optmgmt (3).
.TP 12
.I T_SCTP_MAX_INIT_RETRIES
sets the maximum number of COOKIE-ACK retransmissions that will be performed
until the destination transport address is abandoned.
This value can be changed for specific connection by providing this option to the
.BR t_accept (3).
.PP
If the provider indicates that connect data can be included in the response to
.BR t_getinfo (3),
the XTI user can provide connection data in the
.I call->udata
parameter.
.\"
.\"
.SS t_bind\fR(3)
.PP
SCTP supports this XTI library call as described in
.BR t_bind (3),
with the additional considerations described here.
.PP
When the XTI user provides a transport endpoint address in
.IR req->addr ,
the address to bind can contain multiple
.B sockaddr_in
structures, each representing a local IP address to which to bind a multi-homed
SCTP transport endpoint.
Each address in the array must have the same
.I req->addr[i].sin_family
and
.I req->addr[i].sin_port
value.
.PP
When the SCTP transport service provider returns the bound address in
.IR ret->addr ,
the address bound can contain multiple
.B sockaddr_in
structures, each representing a bound local IP address.  The SCTP conforming
transport service provider will return the same values in each
.I ret->addr[i].sin_family
and
.I ret->addr[i].sin_port
fields.
.\"
.\"
.SS t_close\fR(3)
.PP
SCTP supports this XTI library call as described in
.BR t_close (3)
without modifications.
.PP
Note: closing a transport endpoint in a connected state will result in an
abortive release of the transport connection.
.\"
.\"
.SS t_connect\fR(3)
.PP
SCTP supports this XTI library call as described in
.BR t_connect (3),
with the additional considerations described here.
.PP
When the XTI user provides a transport endpoint address to which to connect in
.IR sndcall->addr ,
the address can be an array of
.B sockaddr_in
structures, each indicating a remote address for the endpoint to which to
connect.
Only one address is necessary to successfully form a multi-homed transport
connection; however, if additional addresses are provided, the transport
connection is initialized in a more secure and reliable fashion.
.PP
SCTP provides a number of options, described in
.IR \(lqOPTIONS\(rq ,
above, that may be included in this XTI call
in the
.I sndcall->opt
parameter to change local ad end-to-end characteristics of the transport
endpoint accepting the connection.
The options of end-to-end significance that can be included in this XTI library
call are:
.TP 12
.I T_SCTP_CKSUM_TYPE
set the type of checksum to be performed on all packets for the connection.
This option is useful if the connecting XTI user is aware that the destination
transport endpoint only supports the older Adler 32 checksum.
.TP 12
.I T_SCTP_ISTREAMS
set the maximum number of incoming streams for the connection.  The peer must
respect this value and negotiate the number of incoming streams to be less
than or equal to this value or the transport connection will fail.
.TP 12
.I T_SCTP_OSTREAMS
set the requested number of outgoing streams for the connection.  The peer may
negotiate a smaller number of outgoing streams depending on its maximum
incoming stream requirements.  It is the XTI user's responsibility to check
the number of outgoing streams in the
.I rcvcall->opt
response or in the
.I call->opt
response from a call to
.BR t_rcvconnect (3).